Electromagnetic waves

The idea

Electromagnetic waves are transverse and form a continuous spectrum. In order of increasing frequency (decreasing wavelength): radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, gamma rays. All travel at the same speed through a vacuum. Uses: radio waves for television and radio, microwaves for satellites and cooking, infrared for heaters and cameras, visible light for fibre optics, ultraviolet for tanning and energy-efficient lamps, X-rays and gamma rays for medical imaging and treatment. UV, X-rays and gamma rays can damage cells: UV ages skin and raises cancer risk; X-rays and gamma rays are ionising.

1. Order the spectrum.
2. Match each wave to a use.
3. Link high frequency to more danger.

Watch out All electromagnetic waves travel at the same speed in a vacuum; they differ in wavelength and frequency.